FIG. 2.

Intracellular growth of wild-type and ΔlemA mutant listeriae. Cells were infected with either wild-type L. monocytogenes 10403s (solid squares) or ΔlemA mutant listeriae (open squares) at a multiplicity of infection of either 0.1 (J774 cells and bone marrow-derived macrophages [BMMΦ]) or 2.0 (Henle 407 cells). One hour later, the cells were washed extensively, and medium containing gentamicin (25 μg/ml) was added. Cells were lysed in sterile water at the time points indicated, and dilutions were plated on BHI agar to determine the total number of cell-associated bacteria per coverslip. Average values ± standard deviation are given. Representative data from one of three separate experiments are shown.